Max Spread for 1ct Round?

[Gearhead]

What is the max spread one can/should get for a 1 Ct stone of course all angles being ideal? I pose this question because if I get it short (less than one carat), I''d like to know what spread diameter should I look for so as long as the depth doesn''t become shallow. I know some dimonds "face" up better than other given equal weight.

 

[Gearhead]

Not sure If I'm using the correct terminology, but I'm looking for the max diameter of the dimond given 1ct size.

 

[Rank Amateur]

Look at a few well-cut rounds.

I think the number you are looking for is about 6.5 mm.

 

[Giangi]

It would be about 6.55 +/- 0.02mm and would be in the 59% range for a 1.00-1.01ct stone.
A well made 1ct is approx. 6.40 to 6.60mm, with 6.50mm being the widely known 'best' measurement. Of course you need to know all the angles/percentages in order to make an informed decision.

 

[Gearhead]

If a well cut 1 carat diamond is judged to be 6.50 mm, and assuming the other 90-95% diamonds sold at malls and diamond centers are not well cut, then what tends to be the MEAN diameter of a 100 pointer at these type stores? Is it more like 6.45mm or 6.40mm or 6.35mm?

 

[aljdewey]

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On 2/5/2004 12:12:57 PM Gearhead wrote:





If a well cut 1 carat diamond is judged to be 6.50 mm, and assuming the other 90-95% diamonds sold at malls and diamond centers are not well cut, then what tends to be the MEAN diameter of a 100 pointer at these type stores? Is it more like 6.45mm or 6.40mm or 6.35mm?
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about 6.25......generally speaking. That's what I found when I went out to the malls.

 

[valeria101]

Gearhead, maybe you would want to run a sercah for Mara's ring. She really got the most of her carats

 

[NewShiny]

Since we're talking spreads here, does anyone know what it should be for a 1.3ct stone? Just wondering - these "in between" numbers are harder to come by.

 

[Gearhead]

----------------[/quote]about 6.25......generally speaking. That's what I found when I went out to the malls.
----------------[/quote]



6.25 mm seriously? That is a pretty big difference? It would be interesting to the numbers on the depth (hidden wieght)as well. I'll do a quick check at some of the local B&Ms and review the certs. If 6.25 is the avg generally speaking for a 1 ct. then you've pretty much summed up what I've learned here on PS the past month - That cut is #1. Funny how it all comes to perspective.

 

[pqcollectibles]

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On 2/5/2004 2:38:40 PM newslick wrote:

Since we're talking spreads here, does anyone know what it should be for a 1.3ct stone? Just wondering - these 'in between' numbers are harder to come by.
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Around 7.1mm for a 1.3 carat.

 

[fire&ice]

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On 2/5/2004 2:43:44 PM Gearhead wrote:


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about 6.25......generally speaking. That's what I found when I went out to the malls.
----------------[/quote]

6.25 mm seriously? That is a pretty big difference?

At least. Some are even worse at the lower end maul stores. Cutters cut to the 1c mark. They will do anything for the weight to be such (which many people don't understand that it does not translate to size "appearance").

 

[pqcollectibles]

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On 2/5/2004 3:53:57 PM fire&ice wrote:

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On 2/5/2004 2:43:44 PM Gearhead wrote:


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about 6.25......generally speaking. That's what I found when I went out to the malls.
----------------

6.25 mm seriously? That is a pretty big difference?

At least. Some are even worse at the lower end maul stores. Cutters cut to the 1c mark. They will do anything for the weight to be such (which many people don't understand that it does not translate to size 'appearance').----------------[/quote]


Yep! Yep! My 6mm, 3/4 carat was as big as a few 1 carats I saw that I know came from Maul stores.

 

[Gearhead]

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On 2/5/2004 2:29:37 PM valeria101 wrote:

Gearhead, maybe you would want to run a sercah for Mara's ring. She really got the most of her carats

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Hey Val,

Mara provided the links to both her threads. I re-read the threads last night and, yes she did maximize her spread. Curious that her stone and choice is not the norm from what I've seen here at PS. Like Mara, I would like to maximize spread so as long as the crown and pavilion angles, depth, etc,....all work out. I remember her threads generating many responses, but in the end the larger than normal table
62%, shallow crown angle 29.9 and good HCA worked for her. I'm slightly intimidated going off on my own in search of a larger table because of the fish eye effect, but I can eyeball that if the stone is local.

I might considering speaking with her jeweler since we live in the Bay Area. Perhaps Mara's jeweler will be able to find me a similar stone just short of a carat. I'll ping Mara and see if might be willing to assist.

rd

 

[someguy]

A while back I looked at the spreads for some diamonds that I found on Blue Nile's site, and averaged the diameters based on cut quality. I was really surprised to see the large variation in diamond diameter, even though the rocks had exactly the same weight... I even saw a few 1ct diamonds that were about 5.8 mm across! Here's a link to the thread: graph . Just take those numbers as an indication of what, on average, is out there...